[PATCH linux dev-5.10 26/35] fsi: scom: Handle FSI2PIB timeout

[Joel Stanley]

On Mon, 8 Mar 2021 at 22:54, Eddie James <eajames at linux.ibm.com> wrote:
>
> From: Joel Stanley <joel at jms.id.au>
>
> When the scom engine indicates a FSI2PIB timeout we can recover by
> writing any value to the the reset register.
>
> Signed-off-by: Joel Stanley <joel at jms.id.au>

This change is incorrect; the logic to do a recovery is already in the
driver. The code needs reworking to run the recovery when a PIB
timeout occurs.

> ---
>  drivers/fsi/fsi-scom.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
> index b45bfab7b7f5..2356a80f7f04 100644
> --- a/drivers/fsi/fsi-scom.c
> +++ b/drivers/fsi/fsi-scom.c
> @@ -38,6 +38,15 @@
>  #define SCOM_STATUS_PIB_RESP_MASK      0x00007000
>  #define SCOM_STATUS_PIB_RESP_SHIFT     12
>
> +/* Values the SCOM_STATUS_PIB_RESP_MASK can take */
> +#define SCOM_PIB_ERR_XSCOM_BLOCKED     0x00004000
> +#define SCOM_PIB_ERR_CHIPLET_OFFLINE   0x00002000
> +#define SCOM_PIB_ERR_PARTIAL_GOOD      0x00006000
> +#define SCOM_PIB_ERR_INVALID_ADDR      0x00001000
> +#define SCOM_PIB_ERR_CLOCK             0x00005000
> +#define SCOM_PIB_ERR_HANDSHAKE         0x00003000
> +#define SCOM_PIB_ERR_TIMEOUT           0x00007000
> +
>  #define SCOM_STATUS_ANY_ERR            (SCOM_STATUS_PROTECTION | \
>                                          SCOM_STATUS_PARITY |     \
>                                          SCOM_STATUS_PIB_ABORT | \
> @@ -250,6 +259,15 @@ static int handle_fsi2pib_status(struct scom_device *scom, uint32_t status)
>         /* Return -EBUSY on PIB abort to force a retry */
>         if (status & SCOM_STATUS_PIB_ABORT)
>                 return -EBUSY;
> +
> +       if (status & SCOM_PIB_ERR_TIMEOUT) {
> +               dev_dbg(&scom->dev, "PIB timeout, recovering\n");
> +               fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
> +                                &dummy, sizeof(uint32_t));
> +               /* Return -EBUSY to force a retry */
> +               return -EBUSY;
> +       }
> +
>         return 0;
>  }
>
> --
> 2.27.0
>